--- zzzz-none-000/linux-3.10.107/fs/nfs/delegation.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/nfs/delegation.c	2021-02-04 17:41:59.000000000 +0000
@@ -20,6 +20,7 @@
 #include "nfs4_fs.h"
 #include "delegation.h"
 #include "internal.h"
+#include "nfs4trace.h"
 
 static void nfs_free_delegation(struct nfs_delegation *delegation)
 {
@@ -40,14 +41,19 @@
 	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
 }
 
-/**
- * nfs_have_delegation - check if inode has a delegation
- * @inode: inode to check
- * @flags: delegation types to check for
- *
- * Returns one if inode has the indicated delegation, otherwise zero.
- */
-int nfs4_have_delegation(struct inode *inode, fmode_t flags)
+static bool
+nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
+		fmode_t flags)
+{
+	if (delegation != NULL && (delegation->type & flags) == flags &&
+	    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
+	    !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
+		return true;
+	return false;
+}
+
+static int
+nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
 {
 	struct nfs_delegation *delegation;
 	int ret = 0;
@@ -55,43 +61,70 @@
 	flags &= FMODE_READ|FMODE_WRITE;
 	rcu_read_lock();
 	delegation = rcu_dereference(NFS_I(inode)->delegation);
-	if (delegation != NULL && (delegation->type & flags) == flags &&
-	    !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
-		nfs_mark_delegation_referenced(delegation);
+	if (nfs4_is_valid_delegation(delegation, flags)) {
+		if (mark)
+			nfs_mark_delegation_referenced(delegation);
 		ret = 1;
 	}
 	rcu_read_unlock();
 	return ret;
 }
+/**
+ * nfs_have_delegation - check if inode has a delegation, mark it
+ * NFS_DELEGATION_REFERENCED if there is one.
+ * @inode: inode to check
+ * @flags: delegation types to check for
+ *
+ * Returns one if inode has the indicated delegation, otherwise zero.
+ */
+int nfs4_have_delegation(struct inode *inode, fmode_t flags)
+{
+	return nfs4_do_check_delegation(inode, flags, true);
+}
+
+/*
+ * nfs4_check_delegation - check if inode has a delegation, do not mark
+ * NFS_DELEGATION_REFERENCED if it has one.
+ */
+int nfs4_check_delegation(struct inode *inode, fmode_t flags)
+{
+	return nfs4_do_check_delegation(inode, flags, false);
+}
 
 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
 {
 	struct inode *inode = state->inode;
 	struct file_lock *fl;
+	struct file_lock_context *flctx = inode->i_flctx;
+	struct list_head *list;
 	int status = 0;
 
-	if (inode->i_flock == NULL)
+	if (flctx == NULL)
 		goto out;
 
-	/* Protect inode->i_flock using the file locks lock */
-	lock_flocks();
-	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
-		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
-			continue;
+	list = &flctx->flc_posix;
+	spin_lock(&flctx->flc_lock);
+restart:
+	list_for_each_entry(fl, list, fl_list) {
 		if (nfs_file_open_context(fl->fl_file) != ctx)
 			continue;
-		unlock_flocks();
+		spin_unlock(&flctx->flc_lock);
 		status = nfs4_lock_delegation_recall(fl, state, stateid);
 		if (status < 0)
 			goto out;
-		lock_flocks();
+		spin_lock(&flctx->flc_lock);
+	}
+	if (list == &flctx->flc_posix) {
+		list = &flctx->flc_flock;
+		goto restart;
 	}
-	unlock_flocks();
+	spin_unlock(&flctx->flc_lock);
 out:
 	return status;
 }
 
-static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
+static int nfs_delegation_claim_opens(struct inode *inode,
+		const nfs4_stateid *stateid, fmode_t type)
 {
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct nfs_open_context *ctx;
@@ -118,7 +151,7 @@
 		/* Block nfs4_proc_unlck */
 		mutex_lock(&sp->so_delegreturn_mutex);
 		seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
-		err = nfs4_open_delegation_recall(ctx, state, stateid);
+		err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 		if (!err)
 			err = nfs_delegation_claim_locks(ctx, state, stateid);
 		if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
@@ -153,15 +186,15 @@
 		if (delegation->inode != NULL) {
 			nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 			delegation->type = res->delegation_type;
-			delegation->maxsize = res->maxsize;
+			delegation->pagemod_limit = res->pagemod_limit;
 			oldcred = delegation->cred;
 			delegation->cred = get_rpccred(cred);
 			clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 				  &delegation->flags);
-			NFS_I(inode)->delegation_state = delegation->type;
 			spin_unlock(&delegation->lock);
-			put_rpccred(oldcred);
 			rcu_read_unlock();
+			put_rpccred(oldcred);
+			trace_nfs4_reclaim_delegation(inode, res->delegation_type);
 		} else {
 			/* We appear to have raced with a delegation return. */
 			spin_unlock(&delegation->lock);
@@ -252,7 +285,6 @@
 	set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 	list_del_rcu(&delegation->super_list);
 	delegation->inode = NULL;
-	nfsi->delegation_state = 0;
 	rcu_assign_pointer(nfsi->delegation, NULL);
 	spin_unlock(&delegation->lock);
 	return delegation;
@@ -283,6 +315,17 @@
 	return nfs_detach_delegation(nfsi, delegation, server);
 }
 
+static void
+nfs_update_inplace_delegation(struct nfs_delegation *delegation,
+		const struct nfs_delegation *update)
+{
+	if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
+		delegation->stateid.seqid = update->stateid.seqid;
+		smp_wmb();
+		delegation->type = update->type;
+	}
+}
+
 /**
  * nfs_inode_set_delegation - set up a delegation on an inode
  * @inode: inode to which delegation applies
@@ -305,7 +348,7 @@
 		return -ENOMEM;
 	nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 	delegation->type = res->delegation_type;
-	delegation->maxsize = res->maxsize;
+	delegation->pagemod_limit = res->pagemod_limit;
 	delegation->change_attr = inode->i_version;
 	delegation->cred = get_rpccred(cred);
 	delegation->inode = inode;
@@ -316,9 +359,11 @@
 	old_delegation = rcu_dereference_protected(nfsi->delegation,
 					lockdep_is_held(&clp->cl_lock));
 	if (old_delegation != NULL) {
-		if (nfs4_stateid_match(&delegation->stateid,
-					&old_delegation->stateid) &&
-				delegation->type == old_delegation->type) {
+		/* Is this an update of the existing delegation? */
+		if (nfs4_stateid_match_other(&old_delegation->stateid,
+					&delegation->stateid)) {
+			nfs_update_inplace_delegation(old_delegation,
+					delegation);
 			goto out;
 		}
 		/*
@@ -336,13 +381,15 @@
 			delegation = NULL;
 			goto out;
 		}
-		freeme = nfs_detach_delegation_locked(nfsi, 
+		if (test_and_set_bit(NFS_DELEGATION_RETURNING,
+					&old_delegation->flags))
+			goto out;
+		freeme = nfs_detach_delegation_locked(nfsi,
 				old_delegation, clp);
 		if (freeme == NULL)
 			goto out;
 	}
-	list_add_rcu(&delegation->super_list, &server->delegations);
-	nfsi->delegation_state = delegation->type;
+	list_add_tail_rcu(&delegation->super_list, &server->delegations);
 	rcu_assign_pointer(nfsi->delegation, delegation);
 	delegation = NULL;
 
@@ -350,6 +397,7 @@
 	spin_lock(&inode->i_lock);
 	nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 	spin_unlock(&inode->i_lock);
+	trace_nfs4_set_delegation(inode, res->delegation_type);
 
 out:
 	spin_unlock(&clp->cl_lock);
@@ -374,7 +422,8 @@
 	do {
 		if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 			break;
-		err = nfs_delegation_claim_opens(inode, &delegation->stateid);
+		err = nfs_delegation_claim_opens(inode, &delegation->stateid,
+				delegation->type);
 		if (!issync || err != -EAGAIN)
 			break;
 		/*
@@ -399,6 +448,8 @@
 {
 	bool ret = false;
 
+	if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
+		goto out;
 	if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 		ret = true;
 	if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
@@ -410,6 +461,7 @@
 			ret = true;
 		spin_unlock(&delegation->lock);
 	}
+out:
 	return ret;
 }
 
@@ -437,14 +489,20 @@
 								super_list) {
 			if (!nfs_delegation_need_return(delegation))
 				continue;
-			inode = nfs_delegation_grab_inode(delegation);
-			if (inode == NULL)
+			if (!nfs_sb_active(server->super))
 				continue;
+			inode = nfs_delegation_grab_inode(delegation);
+			if (inode == NULL) {
+				rcu_read_unlock();
+				nfs_sb_deactive(server->super);
+				goto restart;
+			}
 			delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 			rcu_read_unlock();
 
 			err = nfs_end_delegation_return(inode, delegation, 0);
 			iput(inode);
+			nfs_sb_deactive(server->super);
 			if (!err)
 				goto restart;
 			set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
@@ -468,7 +526,7 @@
 
 	delegation = nfs_inode_detach_delegation(inode);
 	if (delegation != NULL)
-		nfs_do_return_delegation(inode, delegation, 0);
+		nfs_do_return_delegation(inode, delegation, 1);
 }
 
 /**
@@ -673,14 +731,12 @@
 	struct nfs_client *clp = server->nfs_client;
 	struct nfs_delegation *delegation;
 
-	filemap_flush(inode->i_mapping);
-
 	rcu_read_lock();
 	delegation = rcu_dereference(NFS_I(inode)->delegation);
 	if (delegation == NULL)
 		goto out_enoent;
-
-	if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
+	if (stateid != NULL &&
+	    !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 		goto out_enoent;
 	nfs_mark_return_delegation(server, delegation);
 	rcu_read_unlock();
@@ -775,19 +831,30 @@
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry_rcu(delegation, &server->delegations,
 								super_list) {
+			if (test_bit(NFS_DELEGATION_RETURNING,
+						&delegation->flags))
+				continue;
 			if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 						&delegation->flags) == 0)
 				continue;
-			inode = nfs_delegation_grab_inode(delegation);
-			if (inode == NULL)
+			if (!nfs_sb_active(server->super))
 				continue;
-			delegation = nfs_detach_delegation(NFS_I(inode),
-					delegation, server);
+			inode = nfs_delegation_grab_inode(delegation);
+			if (inode == NULL) {
+				rcu_read_unlock();
+				nfs_sb_deactive(server->super);
+				goto restart;
+			}
+			delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 			rcu_read_unlock();
-
-			if (delegation != NULL)
-				nfs_free_delegation(delegation);
+			if (delegation != NULL) {
+				delegation = nfs_detach_delegation(NFS_I(inode),
+					delegation, server);
+				if (delegation != NULL)
+					nfs_free_delegation(delegation);
+			}
 			iput(inode);
+			nfs_sb_deactive(server->super);
 			goto restart;
 		}
 	}
@@ -835,7 +902,7 @@
 	flags &= FMODE_READ|FMODE_WRITE;
 	rcu_read_lock();
 	delegation = rcu_dereference(nfsi->delegation);
-	ret = (delegation != NULL && (delegation->type & flags) == flags);
+	ret = nfs4_is_valid_delegation(delegation, flags);
 	if (ret) {
 		nfs4_stateid_copy(dst, &delegation->stateid);
 		nfs_mark_delegation_referenced(delegation);
@@ -843,3 +910,28 @@
 	rcu_read_unlock();
 	return ret;
 }
+
+/**
+ * nfs4_delegation_flush_on_close - Check if we must flush file on close
+ * @inode: inode to check
+ *
+ * This function checks the number of outstanding writes to the file
+ * against the delegation 'space_limit' field to see if
+ * the spec requires us to flush the file on close.
+ */
+bool nfs4_delegation_flush_on_close(const struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_delegation *delegation;
+	bool ret = true;
+
+	rcu_read_lock();
+	delegation = rcu_dereference(nfsi->delegation);
+	if (delegation == NULL || !(delegation->type & FMODE_WRITE))
+		goto out;
+	if (nfsi->nrequests < delegation->pagemod_limit)
+		ret = false;
+out:
+	rcu_read_unlock();
+	return ret;
+}